1. Field of the Invention
The present invention relates to a one-piece golf ball, more particularly to a one-piece golf ball having a paint film formed on the surface of the golf ball body.
2. Description of the Related Art
Conventionally, the one-piece golf ball is used as a golf ball in a golf driving range. If the one-piece golf ball is used in the golf driving range for a long term, the one-piece golf ball changes in color because of being exposed to the sun-light and the elements. Also, the paint film formed on the golf ball body occasionally peels off, because the one-piece golf ball is used while being repeatedly hit and washed. The coloring and the peeling of the paint film should be avoided, because they will give an impression that the golf ball is deteriorated. Especially, in the case that the paint film peels off, the golf ball body is directly exposed to the sun-light and the elements, the golf ball body is actually deteriorated, thus the performance of the golf ball is lowered. Further, it is required in a higher degree to enhance the repulsion of the one-piece golf ball body, thereby improving the flying performance of the one-piece golf ball, because the one-piece golf ball has lower flying performance, compared with the two-piece golf ball and the wound core golf ball.
Under these circumstances, various one-piece golf balls have been proposed. For example, Japanese unexamined patent publication No. 2001-212262 discloses the golf ball where the adhesion of the paint film is improved by formulating a silane-coupling agent into the golf ball body. In addition, Japanese unexamined patent publication Nos. H07-51403 and 2001-17576 disclose the golf ball where the blue pigment is blended in the golf ball body, and the anti-oxidant, the light-stabilizer and the fluorescent brightener or the like are formulated in the clear paint film, thereby improving the adhesion of the paint film as well as imparting the bright whiteness to the golf ball.